Stable aquarium water temperatures are often taken for granted. Trusting in aquarium equipment to keep water temperatures stable, water temperature is monitored less frequently compared to other vital water parameters.

Why is stablewater temperatureso important totropical aquariumfish?

A. Fish are cold-blooded animals that rely on the temperature of the water to regulate bodily functions. Dramatic change in water temperature severely stresses fish and this stress can compromise fish immune systems, or even result in fish loss.

But if you came home one day to find your aquarium heater or chiller had failed, would you know what to do? The following emergency temperature tips can help prepare you for such unforeseen events.

Life support system in crisis
Without the aid of a
heater or
chiller, aquarium water temperature will naturally reach ambient room temperature. Most tropical species can adjust to and tolerate gradual temperature change. However, depending on the time of year or the temperature/environmental control system of the home, aquariums can experience harmful temperature changes. Always check and record aquarium water temperature before pursuing any corrective measures. Monitor water temperature to determine any temperature shift.

Corrective steps Unless you are experiencing a long-term power outage lasting over a 3-hour period, it is best to leave your aquarium alone. It is unlikely that a power outage of less than 3 hours will significantly affect aquarium water quality. Attempting to "correct" the temperature during a short-term power outage may stress the fish more than the outage itself.

Marine corals and invertebrates are more sensitive to rising water temperatures. During summer, it is a good idea to keep a few frozen water bottles in the freezer. In a pinch, you can place these in your aquarium to help slowly bring temperatures back down to an acceptable range.

When aquarium water temperatures are too warm:

Increased fish activity (hyperactivity)

Fish gasping at surface or "yawning"

Color change

When aquarium water temperatures are too cool:

Sluggish fish behavior or lack of vigor

Fish laying on side or occupying lower regions of aquarium

Color change

Too cold? Protect your aquarium inhabitants from the chill during a long-term power outage. Consider wrapping a blanket around your aquarium to prevent rapid heat loss.

Preventive steps Keep on top of
water quality in addition to monitoring and maintaining stable water temperature. While a single episode of a temperature shift may seem simple to correct, it may have longer lasting effects. The stress experienced by aquarium inhabitants can often make them more sensitive to declining water quality and thus more susceptible to potential illnesses. Pay particular attention if you have a smaller aquarium system.

Invest in a temperature alert device such as the
Big Digital Temp Alert. This compact digital thermometer has an audible alarm that alerts you when water temperature is too high or too low.

If your aquarium relies on high output light fixtures or other equipment that generate heat, be sure to provide adequate ventilation. Install a
cooling fan to exhaust heat generated by these devices.